The present invention relates to a discharge type display apparatus such as a plasma display panel utilizing gas discharge for display.
Plasma display panels (PDPs) are typically known as a discharge type display apparatus utilizing a three-component mixed gas made of He (helium), Ne (neon) and Xe (xenon), as described illustratively in Japanese Unexamined Patent Publication No. Hei 6-342631. With this kind of discharge type display apparatus, the volume ratio of He to Ne is set for 6:4 through 9:1, and the volume ratio of Xe to the entire gas is set for 1.5 through 10%. The PDP of the disclosed technique envisages attaining a high level of radiation efficiency on a reduced drive voltage (sustain voltage).
One disadvantage of the PDP cited above is that the mixed ratio of the mixed gas used therein leads to an increased firing voltage accompanied by a reduced operating margin. The operating margin is defined as a voltage range from the lowest to the highest sustain voltage. The lowest sustain voltage is determined by a firing voltage, i.e., a minimum voltage required to illuminate specific cells (called light-emitting cells hereunder) selected during an addressing period. The highest sustain voltage is determined by a maximum voltage that will not let illumination be disabled primarily by self-erasure caused by a wall charge. A surge in the firing voltage and a drop in the operating margin are bound to pose constraints on the setting of sustain voltage values. This arrangement has not been quite satisfactory in terms of the ease of drive.
Typically, AC (alternate current) type PDPs are driven in general by having light-emitting cells selected by write discharge operations. At the write discharge stage, it is necessary to develop exact quantities of charges in electrodes.
However, it is general practice not to furnish the AC type PDP with barrier ribs in a direction perpendicular to address electrodes. At the time of write discharge, required quantities of charges may not be formed in the selected light-emitting cells because of the diffusion of charges (called cross talk) to adjacent cells not divided by barrier ribs. That is, cross talk also reduces the operating margin by restricting its upper limit.
Such problems have not been dealt with by the above-cited conventional technique. It is therefore an object of the present invention to overcome the above and other disadvantages of the prior art and to provide a display apparatus capable of minimizing drops in the operating margin caused by cross talk while reducing defective charges provoked by cross talk.
In carrying out the invention and according to one aspect thereof, there is provided a discharge type display apparatus for displaying images by means of discharges in a discharge gas enclosed in discharge spaces, wherein the discharge gas is a mixed gas including at least Xe, He and Ne, and wherein a mixed ratio of He to Ne is set for about 50% in volume at most.
The inventive discharge type display apparatus above suppresses adverse effects of cross talk so as to keep the upper limit of the operating margin approximately constant, thereby maintaining a wide operating margin.
Other objects, features and advantages of the invention will become more apparent upon a reading of the following description and appended drawings.